This invention relates to elastomeric blends and to a method for making them. The blends comprise acrylic rubber and another elastomer which can be nitrile rubber, hydrogenated nitrile rubber, a fluoroelastomer, a silicone rubber or a fluorosilicone rubber. The elastomer compositions all have excellent resistance to the degrading effects of oil and heat.
Elastomers which possess superior properties with regard to service temperature and low oil-swell are often referred to as "extreme-service" elastomers. Typical of these materials are fluorocarbon rubbers, fluorosilicone rubbers and silicone rubbers. A principal drawback of these materials is their high cost.
Other elastomers, such as nitrile rubber, have excellent oil-swell properties, but do not have high service temperatures. Still others, such as acrylic rubber, have fairly high service temperatures as well as very good oil resistance.
A desirable result, therefore, is a blend of elastomers which can produce a composition which has the properties of resistance to both heat and oil at a reasonable cost.